ENVIRONMENTALLY-INDUCED KIDNEY DISEASES
The extent of the contribution of environment in causing renal
disease is unknown. This is largely due to the following: 1- The fact that
multiple environmental factors could be working together, 2- Difficulty in
confirming and quantifying the exposure to a certain environmental toxin;
and 3- The lack of specific clinical or pathologic presentation of different
environmental toxin.
In the USA, 19% of patients with end stage renal failure have
disease of unknown cause and in 30 per cent of those presenting with
glomerulonephritis the aetiology is unrecognized, possibly environmental
toxins are responsible at least in part for these cases.
The kidney is more prone to environmental toxins for the following
reasons:
1- The kidney is the principal organ for excretion of different toxins;
2- High renal blood flow;
3- Extensive surface of endothelial contact with toxins;
4- Positive intraglomerular hydrostatic pressure;
5- The medullary counter-current multiplier system leading to more
accumulation of toxic agents and their metabolites in the renal
medulla.
The environmentally-induced renal injury may be tubulo-
interstitial, glomerular or combined. Tubulo-interstitial lesions may be in
the form of acute tubular necrosis (such as exposure to high concentration
of mercury) or chronic tubulointerstitial nephritis (such as chronic
exposure to low doses of lead). Glomerular lesions may be due to direct
toxicity (such as deposition of gold in basement membrane and silica in